Winding device

ABSTRACT

A DIFFERENTIAL SURFACE WINDING DEVICE FOR WINDING A NUMBER OF ROLLS OF PRESSURE-SENSITIVE ADHESIVE TAPE UPON CORES MOUNTED IN AXIALLY SPACED RELATION FROM ONE ANOTHER UPON THE SAME MANDREL, WHICH COMPRISES A MANDREL ON WHICH THE TAPE CORES ARE ROTATABLY MOUNTED, MEANS ASSOCIATED WITH THE MANDREL FOR MAINTAINING THE CORES AND THE TAPE ROLLS WOUND THEREON IN DEFINE POSITIONS AXIALLY SPACED FROM ONE ANOTHER ON THE MANDREL, A DRIVING ROOL PRESENTING A RELATIVELY COMPRESSIBLE AND RESILIENT PERIPHERAL SURFACE PORTION ADAPTED TO CONTACT ALL OF THE CORES AND/OR TAPE ROLLS ON SAID MANDREL, AND MEANS FOR URGING THE MANDREL AND THE DRIVING ROLL TOWARD ONE ANOTHER WITH SUFFICIENT FORCE TO PROVIDE INTIMATE DRIVING CONTACT BETWEEN THE DRIVING ROLL AND THE TAPE ROLLS. THE RESILIENT PERIPHERAL SURFACE PORTION OF THE DRIVING ROLL IS SUFFICIENTLY RESILIENT AND COMPRESSIBLE TO ALLOW A TAPE ROLL WHICH ACQUIRES A SOMEWHAT LARGER DIAMETER TO SINK FURTHER INTO THE DRIVING ROLL THAN THE TAPE ROLLS OF SMALLER DIAMETER WHILE MAINTAINING DRIVING CONTACT WITH EACH OF THE TAPE ROLLL ON THE MANDREL. IN ADDITION, THE RESILIENT DRIVING ROLLS OR CORES IN OF THE TAPE ROLLS AT THE POINTS WHERE THE TAPE BEING WOUND ON THE ROLLS FIRST CONTACT THEIR RESPECTIVE ROLLS OR CORES IN SUCH A WAY AS TO EXPRESS THE AIR FROM BETWEEN THE CONVOLUTIONS OF THE ROLLS AS THE TAPES ARE BEING WOUND.

J. J. HALL WINDING DEVICE Nov. 14, 1972 5 Sheets-Sheet 1 Filed Julv 2,1970 ATTORNEY INVENTOR JOSEPH u. #4

5 Sheets-Sheet 2 i J. J. HALL WINDING DEVICE Nov; 14, 1972- Filed Julv2, 1970 I J..J. HALL 3,702,687

WINDING DEVICE 5 Sheets-Sheet 4.

Nov. 14, 1972 Filed July 2, 1970 INVENTOR Joss q Jflpz;

Y %2 i ATTbRNEY N\\ EFF NW m n, UQTPLP J. J. HALL WINDING DEVICE UnitedStates Patent Office 3,702,687 Patented Nov. 14, 1 972 Int. Cl. B651119/04 US. Cl. 242-563 25 Claims ABSTRACT OF THE DISCLOSURE Adifferential surface winding device for winding a number of rolls ofpressure-sensitive adhesive tape upon cores mounted in axially spacedrelation from one another upon the same mandrel, which comprises amandrel on which the tape cores are rotatably mounted, means associatedwith the mandrel for maintaining the cores and the tape rolls woundthereon in definite positions axially spaced from one another on themandrel, a driving roll presenting a relatively compressible andresilient peripheral surface portion adapted to contact all of the coresand/or tape rolls on said mandrel, and means for urging the mandrel andthe driving roll toward one another with suficient force to provideintimate driving contact between the driving roll and the tape rolls.The resilient peripheral surface portion of the driving roll issuificiently resilient and compressible to allow a tape roll whichacquires a somewhat larger diameter to sink further into the drivingroll than the tape rolls of smaller diameter while maintaining drivingcontact with each of the tape rolls on the mandrel. In addition, theresilient driving roll contacts all of the tape rolls at the pointswhere the tapes being wound on the rolls first contact their respectiverolls or cores in such a way as to express the air from between theconvolutions of the rolls as the tapes are being wound.

This application is a continuation-in-part of my copending US. patentapplication, Ser. No. 701,196, filed J an. 29, 1968, now abandoned.

The present invention relates to devices and methods for windingpressure-sensitive adhesive tape upon itself around a cylindrical corewith the adhesive side of the tape facing inwardly or toward the core,and more particularly to such devices wherein a multiplicity of tapesare cut from the same sheet and then wound into rolls utilizing two ormore winding mandrels, each of which supports a plurality of rolls.

conventionally, a large number of such pressure-sensitive adhesive tapesare slit from a relatively wide sheet having one of its surfaces coatedwith a layer of adhesive. For instance, approximately 60 tapes one-halfinch wide may be slit from an adhesive coated sheet approximately 30inches wide; and then wound alternately, 30 rolls each, upon a pair ofwinding mandrels. At least two mandrels are used in this manner to avoidthe difficulties which would arise in attempting to wind all 60 tapesupon a single mandrel. Basically the problem would be in attempting toprevent contiguous or adjacent rolls from sticking to one another, orfrom becoming fouled on one another and thereby causing machine downtime.

Many difficulties have been encountered in the operation of this type ofdevice, both from the standpoint of chicient operation with minimumwaste, and from the standpoint of consistently producing a high-qualityproducts. For instance, in producing film-backed tapes, problems havedeveloped in both of these areas due to variations in the thickness ofthe films supplied by film manufacturers. These variations commonlyoccur not only lengthwise of a relatively long roll of film butwidthwise, or from edge to edge, of the film. In addition, variations inthe thickness of the adhesive layer also occur widthwise and lengthwiseof the film, particularly if the amount of adhesive deposited depends tosome extent upon the thickness of the backing. Variations in thicknesscause variations in the size of the rolls being wound on the samemandrel and this creates variations in winding tension and rolltightness. As a result, tape rolls are produced which are unsatisfactoryboth in function and appearance.

Rolls which are wound too tight tend to collapse side- Wise to relievethe tension built into the roll structure, especially when subjected toheat or high humidity conditions. This type of failure is called dishingor telescoping of the rolls and may render the tape completely unusable.Certainly, the appearance of the rolls is entirely unsatisfactory. Rollswhich are wound too loosely, lose their shape and become humped, or outof round, and develop gaps between the various convolutions of the tape.This, not only is unacceptable from the standpoint of appearance, but itcauses the tape to function poorly in dispensing and may be the cause oftape deterioration. Loose winding also creates rough side surfaces onthe roll since the tape is somewhat free to wander axially duringwinding.

It has been determined that there is an acceptable range of tightnesswithin which the tape, not only appears tightly wound in cylindricalroll form with staright side surfaces, but does not telescope, hump orotherwise lose its shape or ability to function. Roll tightness for thispurpose normally is evaluated by a hardness: test in which theresistance of the roll to penetration by an instrument is measured.Hardness standards then are established for determining acceptable rolltightness for each type of tape.

In order to achieve optimum appearance even within the range ofacceptable roll hardness for a given type of tape, it also is importantto express out the air bubbles which tend to form between the tapeconvolutions as the tape is being wound on the roll. This isparticularly important for clear tapes having backing films ofpolypropylene, polyethylene terephthalate, and the like.

I have invented a differential surface winder for simultaneously windinga large number of rolls of pressuresensitive adhesive tape slit from thesame sheet upon a single mandrel in a way which will insure thatvirtually all of the rolls will have a tightness falling within theacceptable range and, in addition, will be free of air bubbles whichdetract from the clarity and general overall appearance of the taperolls and a method to accomplish this. In my device, the tapes are woundat a substantially constant linear speed on each of the rolls along themandrel, with the result that winding tension is maintainedsubstantially constant from tape to tape extending widthwise of theoriginal sheet or lengthwise of the mandrel. In order to accomplishthis, means are provided for allowing for or absorbing variations in thethickness of the sheet with consequent variations in the angular speedof the tape rolls, without substantially aflFecting linear speed orwinding tension. Thus, the tape rolls normally are wound undersubstantially constant tension from beginning to end of the roll,although this tension can be zero or even slightly negative since thetape is under control of the driving roll which is in contact with theperipheries of the tape rolls, themselves, and the linear speed of thesurface of the driving roll can be lowered to the point where tension isnegative. In addition, the tapes are wound on each roll in such a waythat air is pressed out from between the convolutions of the roll as thetape is being wound.

The differential surface winder of my invention comprises a mandrel onwhich the tape cores are rotatably mounted. It is important that themandrel possesses an outer diameter small enough to allow the tape coresto turn freely thereon. As a result, the individual tape rolls are freeto assume different angular speeds and allow the linear speeds of thetapes being wound on each of the rolls to be governed by the linearspeed of the surface of the driving roll and thereby maintainedsubstantially constant from tape to tape extending widthwise of theoriginal sheet from which the tapes are slit. Preferably, to maintainmaximum control over winding conditions, the tapes are wrapped around asubstantial portion of the periphery of the driving roll with thenonadhesive side of the tapes in contact with the resilient surface ofthe driving roll prior to any contact between the adhesive side of thetape and the tape rolls. The area of contact between the wrapped tapesand the surface of the driving roll, and the relative coefiicients offriction of the non-adhesive surfaces of the tapes and the surface ofthe driving roll, are such as to normally prevent slippage between thetape and the driving roll during winding of the tape, so that the tapesare advanced at the linear speed of the surface of the driving roll.

Preferably, the mandrel is mounted in such a way as to be freelyrotatable and is driven through the tape by direct pressure from thedriving roll. Normally, the mandrel is urged toward the driving roll forthis purpose. An effective device for accomplishing this is a pressureroll or set of pressure rolls disposed above the mandrel, and in axialparallelism therewith, in such a way that pressure normally is applieddirectly to the tape rolls themselves and through the tape rolls urgesthe mandrel towards the driving roll. Preferably, the resilientperipheral surface portion of the driving roll is formed of rubber andpossesses a Short-A durometer hardness of about 2-535. The resilientportion of the driving roll may be in the form of a hollow cylinder ofrubber surrounding a central cylindricalhub portion of the driving roll,and normally is at least about one-quarter inch thick. However, anyother resilient roll structure capable of performing this function maybe employed.

Preferably, also, the pressure means for urging the tape rolls towardthe driving roll is a set of resilient pressure wheels mounted forrotation independently of one another in axial parallelism with respectto the mandrel on the opposite side of the mandrel from the drivingroll. The pressure wheels are arranged so that no one wheel will contactmore than one of the tape rolls. This is assured when the axial width ofthe pressure wheels is less than the axial distance between the taperolls. With the pressure being applied independently to each of the taperolls through independently rotating pressure wheels, the tape rolls arecompletely free to adjust with respect to one another on the mandrel tocompensate for variations in the thickness of the tape being wound, andthe like. Furthermore, complete control of the tape windings is assuredby the fact that the resilient pressure wheels will compensate for thelarger roll diameters and allow pressure to be applied directly to rollsof smaller diameter and thereby assure that the smaller rolls arepressed into the resilient peripheral portion of the driving roll tosurfacewind the tape while expressing the air from between itsconvolutions in accordance with this invention.

In a preferred form of this invention the mandrel includes a series ofmembers which are completely retractable into the mandrel to allow freeaxial movement of the tape cores onto the mandrel, and extensible withrespect to the mandrel to position the tape rolls and prevent theirfurther axial movement while allowing free rotation of the cores on themandrel. Preferably these spacing members are adapted to be movedinwardly and outwardly of the mandrel as a set so that the tape coresand rolls may be easily positioned on and removed from the mandrel. In apreferred structure for this purpose the spacing members are in the formof spaced teeth or flanges extending outwardly from a pair of opposedcomblike spacing bars. In another form of this invention the mandrel maybe in the form of expandable halves transversely slotted to position thetape rolls axially.

It is an important feature of the preferred embodiment of this inventionthat the resilient peripheral surface portion of the driving rollcontacts all of the tape rolls at the points where the tapes being woundon the rolls first contact their respective tape rolls or cores. Thismakes it possible to Wind the tape on the rolls in such a way as toexpress the air from between the convolutions of the rolls as the tapeis being wound. The tape is led into the nip, formed between the drivingroll and its respective core or tape roll and wound on the tape roll bythe motion imparted to the tape by virtue of its contact with theresilient peripheral surface portion of the driving roll. As statedabove, the mandrel and the driving roll are urged together withsufficient force that the tape rolls being wound on the mandrel sink atleast slightly into the resilient portion of the driving roll. Largerrolls occasioned by thicker sections of the film or tape being wound areadapted to sink further into the resilient portion of the driving roll.However, regardless of the size of the tape rolls the peripheral speedof the tapes being wound is governed by the peripheral speed of thesurface of the driving roll and thereby is maintained substantiallyconstant since the tape rolls are freely rotatable on the mandrel andare caused to rotate only by virtue of their contact with the drivingroll through the tapes being wound thereon. As explained hereinbefore,this allows individual tape rolls to assume different angular speeds tocompensate for variations in their diameter. The method of winding tapein accordance to this invention and the apparatus employed for thispurpose will be described rnore fully hereafter.

Other and further objects and advantages of this invention will appearto one skilled in that art from the following description and claimstaken together with the drawings wherein.

FIG. 1 is a schematic view partly in section and partly in sideelevation of differential surface winding apparatus according to oneembodiment of this invention.

:FIG. 2 is a fragmental end elevational view of the foregoing apparatustaken from the line 22 of FIG. 1, with parts broken away and omitted forthe sake of clarity.

FIG. 3 is an enlarged schematic sectional view of a portion of theapparatus of FIG. 1 showing the contact between the resilient peripheralportion of the driving roll and the tape rolls during winding.

FIG. 4 is an enlarged schematic sectional view similar to that of FIG. 3and showing greater distortion of the resilient, portion of the drivingroll due to an enlarged tape roll.

FIG. 5 is a view in perspective of mandrel according to a preferredembodiment of this invention and showing the spacing members retracted.

FIG. 6 is a perspective view similar to that of FIG. 5 of a portion ofthe mandrel of FIG. 5 but showing the spacing members extended in such away as to position the tape rolls or cores axially on the mandrel.

FIG. 7 is an exploded perspective view of an end portion of the mandrelof FIG. 6 showing the relationship between the mandrel and the comb-likespacing bars which present the spacing members.

FIG. 8 is an elevational view of a portion of one end of the mandrel ofFIG. 5.

FIG. 9 is an enlarged sectional view taken along the line 99 of FIG. 8.

FIG. 10 is a similar enlarged sectional view taken along the line 1010of FIG. 13.

FIG. 11 is another enlarged sectional view taken along the line 11-11 ofFIG. 13.

FIG. 12 is a similar enlarged sectional view taken along line 1212 ofFIG. 13.

FIG. 13 is an enlarged view partly in longitudinal section and partly inelevation showing the assembled parts at one end of the mandrel of FIG.with the spacing bars retracted to allow the tape cores to be positionedon the mandrel.

FIG. 14 is an enlarged view similar to FIG. 13 but showing the spacingbars extended to position the tape cores.

FIG. 15 is an enlarged view partly in section and partly in elevation ofa mandrel according to a somewhat different embodiment of thisinvention.

FIG. 16 is a partially broken away sectional view taken along the line16-16 of FIG. 15.

FIG. 17 is an end elevational view of a differential surface winderaccording to still a different embodiment of this invention.

FIG. 18 is an enlarged view in perspective of an end portion of thepositioning comb of the apparatus of FIG. 17.

FIG. 19 is a fragmental end elevation view partly in section similar'toFIG. 2 and showing apparatus according to a somewhat differentembodiment of this invention.

FIG. 20 is a somewhat schematic end view, partly in section, similar tothe left hand part of FIG. 1 and partly broken away to show the guidetrack for the pressure applying head.

FIG. 21 is an enlarged front elevation view, partly in section, showingthe arrangement of the pressure wheels on their control shaft and theway in which they contact the tape rolls mounted on the mandrel.

FIG. 22 is an enlarged broken away sectional view of one end of themandrel of the embodiment of FIG. 19.

FIG. 23 is an end view partly in section and partly in elevation, takenalong the line 23-23 of FIG. 22.

FIG. 24 is a sectional view taken along the line 2424 of FIG. 22 andshowing the mandrel expanded to prevent the tape rolls from movingaxially with respect thereto.

FIG. 25 is a sectional view similar to FIG. 24 showing the mandrel withits halves retracted to allow the tape rolls to move axially.

FIG. 26 is an exploded view of the parts at one end of the mandrel of'FIG. 22.

Referring to FIGS. 1-14 of the drawings and in particular FIGS. 1-4thereof, there is shown differential surface winding apparatus accordingto a preferred embodiment of this invention. The apparatus, shown mostclearly in FIG. 1, includes a pair of mandrels 21 each of which isassociated with a dilferential surface winding device according to thisinvention which comprises the mandrel 21 itself, a driving roll 22 belowthe mandrel, and a weighted roll 23 above the mandrel. Similarly, onlyone end portion of the lower winding device is fully shown in FIG. 2since the other end is identical and the central portion thereof merelyis a continuation of that which is shown.

A relatively wide adhesive coated sheet 24 is drawn from a supply rollthereof, not shown, over a pair of freely rotating rubber covered pullrolls 25 and 26 and thence over a pair of spaced rotatably mountedsupport rolls 27 and 28 with the adhesive side of the sheet facing thesupport rolls. A set of slitting knives 29 are positioned above thesupport rolls 27 and 28 in such a way that the knives can be moved intocontact with the top surface of the adhesive sheet to slit the sheetinto relatively narrow tapes. For instance, as indicated hereinbefore,the original sheet may be about 30 inches wide or wider, and may be slitinto approximately 60 tapes 30, one-half inch wide by a set of 59slitting knives. The resulting tapes are drawn from the knives 29 andaround a relatively large driven platen roll 31. As the tapes passaround the platen roll 31 alternate tapes are separated to form two setsof tapes each consisting of one-half of the total number slit from thesheet with adjacent tapes spaced from one another by a distanceapproximately equal to the width of each of the tapes. One set of thesetapes is led around the driving roll 22 of the lower winding device tothe left of the platen roll, and the other set is led around the drivingroll 22 of the upper winding device above the platen roll. Thereafter,each of the sets is wound into individual tape rolls 32 as will bedescribed in detail for the lower winding device.

The set of tapes 30 is drawn around the driving roll 22 in such a waythat each of the tapes in the set is wrapped around a substantialportion of the outer surface of the roll with the non-adhesive side ofthe tape facing the driving roll 22. Then the tapes are led into the nipbetween the driving roll 22 and the mandrel 21, while still in contactwith the driving roll, and thence wound on conventional cylindricalcores 33 mounted in the desired spaced relation on the mandrel 21.During this process the mandrel 21 is urged toward the driving roll bythe weighted roll 23 mounted above the mandrel which, in turn, is urgeddownwardly at each of its ends, in such a way as to exert a constantdownward force applied relatively evenly from end to end of the mandrel.This force is applied to the mandrel 21 through the tape rolls 32 orcores 33, themselves, which are in contact with the weighted roll 23.

The driving roll 22 is mounted on a shaft 35 which is driven from aconventional source of power such as an adjustable electric motor, notshown. The shaft 35 is mounted for rotation in frames 36 at each end ofthe device. The driving roll 22 comprises a central cylindrical hubportion 37 of a rigid material such as steel, and a resilient peripheralsurface portion 38 in the form of a hollow cylinder of rubber, or thelike, possessing a Shore' A durometer hardness of about 25-35. Theresilient cyl inder 38 should be thick enough to allow the desireddeformation during winding as will be described more fully hereafter. Arubber cylinder of this hardness and approximately one-quarter inchthick is useful for this purpose although greater thicknesses in theneighborhood of onehalf inch or more may be more desirable. The mandrel21 is mounted in such a way as to be freely rotatable through a pair ofopposed cam follower rolls 39, one threaded into each end of themandrel. Each of the follower rolls 39 rides in a vertical guide track41 secured to the inside of its corresponding end frame 36. The weightedroller 23, which may be a conventional steel idler roll, is mounted forrotation on a shaft 42 which is rotatively supported at its ends in apair of slides 43, each of which is guided for vertical movement in avertical guide 44 attached to the outside of each of the end frames 36.In order to assure that the weighted roller 23 applies a constant andrelatively even force downwardly upon the tape rolls 32 being wound onthe mandrel, each of the slides 43 is pulled downwardly by a chain 45attached to the arm of an eddy current clutch, not shown, which iscontrolled so as to deliver a balanced pulling force on each of thechains 45. Therefore, the weighted roll 23 exerts a downward force uponthe tape rolls 32 which is, not only due to its weight, but complementedand regulated by the eddy current clutch arrangement just described.

A preferred form of mandrel 21 in accordance with this invention isshown in more detail in FIGS. 5-14. This mandrel comprises an elongatedbarrel 46 having two halves almost separated, by a pair of opposedlongitudinal slots 47 designed to hold a corresponding pair of top andbottom guide bars 48, which in turn, present a multiplicity of spacingmembers in the form of teeth or flanges 49. The halves of the barrel 46of the mandrel are connected by a central rib 51 which remains betweenthe slots 47. When the top and bottom guide bars 4:8 are positioned inthe longitudinal slots 47 in such a way that they are both in contactwith the rib 51 the spacing teeth 49 are retracted within the normalouter diameter of the mandrel. This allows a full set of conventionalcylindrical tape cores 33 to be slid onto the mandrel from one endthereof and into the desired spaced relationship with one anotherthereon. The spacing between adjacent teeth 49 on the spacing bars 48 issuch as to freely accommodate one of the cylindrical cores 33. Each ofthe spacing bars 48 defines a recess 52 adjacent each of its ends inwhich a compression spring 53 is located which presses inwardly againstthe rib 51. The springs 53 are so designed that they normally urge thebars 48 outwardly away from the rib. The maximum outward extension ofthe bars 48 and their spacing teeth or flanges 49 is controlled by pairsof positioning pins 54 as shown most clearly in FIGS. 12-14 which extendthrough holes 54a in the barrel 46 and through a corresponding pair ofvertical slots 55 in each of the spacing bars 48. In the position shownin FIG. 14, these pins 54 are shown limiting the outward movement of thespacing bars 48.

The extension and retraction of the spacing bars 48 is controlled by apair of cam plates 56 at each end of the mandrel. Each of these camplates 56, in turn, defines upper and lower inclined cam shoulders 57adapted to cooperate with a corresponding inclined shoulder 53 at theend of each of the spacing bars 48. The cam plates 56 are mounted foraxial movement in the mandrel 21 in a slot 59, provided for thispurpose, in such a way that when the cam plates 56 are moved inwardlyboth of the spacing bars 48 are caused to move inwardly against theforce of the compression springs 53 and therefore to assume theirretracted position, shown most clearly in FIGS. 5 and 13, in which thetape cores 33 are free to move axially over the mandrel. When the camplates 56 are moved outwardly to the position most clearly shown inFIGS. 6 and 14, the two spacing bars 43 are able to move radiallyoutwardly under the force of the compression springs 53 to theirextended position Where the spacing teeth or flanges 49 protrude betweenthe tape cores 33 and thereby prevent their axial movement with respectto the mandrel. However, in this position of the spacing bars thediametric distance between the lands or fiat portions 61 between theteeth 49 is at least slightly less than the inner diameters of the cores33 so that the cores are free to rotate with respect to the mandrel 21.Of course, it also is necessary for this purpose that the outer diameterof the barrel portion 46 of the mandrel allow the cores 33 to rotatethereon and that the distance between the spacing teeth 49 be such thatthe teeth do not bind the cores or otherwise prevent them from rotatingfreely on the mandrel. To assure that the cam plates 56 assume theproper position axially inwardly and outwardly with respect to thepositioning bars 48, their movement in each direction is limited by aset of stop pins 62 extending through holes 62a provided for thispurpose in the barrel 46 of the mandrel and thence through horizontalslots 63 in the cam plates which are designated to limit the movement ofthe cams when they are operated as described above. The exposedoutermost surfaces of the cam plates 56 present 'a series of smalltransverse serrations 64 for gripping the plates to move them axiallyfor this purpose.

FIG. 15 shows a mandrel according to a somewhat different embodiment ofthe invention which is very much the same as that described hereinbeforewith the basic difference that it comprises a hollow barrel 65. Thisconstruction is best adapted for winding larger diameter tape rolls oncores in the order of 3 inches in diameter or larger. In this mandrelthe longitudinal grooves 47 only extend partially through thecylindrical barrel 65 in such a way that there are two shelf-likeportions 66 of the barrel below each of the grooves 47 corresponding tothe single rib 51 of the embodiment of FIGS. 1-14. It also will be seenthat, due to the large size of the cam plates 56 in this device, twomore positioning pins 62 are included at each end of the mandrel forcontrolling the axial movement of the cam plates.

In the embodiment shown in FIG. 17, each of the tape rolls 32 is mountedon a cylindrical core which is free to rotate on a mandrel 67, asdescribed hereinbcfore, but instead of using spacing members whichretract into the mandrel 67, a separate spacing comb 68 is provided.This comb 68 presents a series of teeth 69 which correspond to the teeth49 of the spacing bars 48 in the foregoing embodiments, and whichposition the tape rolls axially between them in the same manner.However, the comb 68 is mounted at its ends on a pair of pins 71, onlyone of which is shown at one end of the comb in FIG. 18, in such a waythat it may be pivoted downwardly into the position shown in FIG. 17 toposition the rolls (or cores) axially of the mandrel, or pivotedupwardly to retract or move the teeth 69 out of the way of the cores orrolls 32 to allow them to be positioned on, or removed from, themandrel. Otherwise the device of this embodiment operates in the samemanner as those of the foregoing figures.

In operation, the cam plates 56 are moved inwardly; i.e., towards thecenter of the mandrel 21 to cam the spacing bars 48 inwardly to theirretracted position, shown in FIG. 13, and the required number ofcylindrical tape cores 33 are slid axially over the mandrel to theirproper location thereon. Then, the cam plates 56 are moved outwardly torelease the spacing bars 48 so that they can move outwardly under theurging of the compression springs 53 to their extended position, shownin FIG. 14, where the flanges 49 on the bars 48 separate the cores 33and retain them in position axially of the mandrel while leaving themfreely rotatable thereon. After the mandrel 21 is placed in positionbetween the driving roll 22 and the weighted roll 23, the adhesive sheet24 is slit into tapes 3G by drawing it under the bank of slitting knives29, the tapes 30 are let around the platen roll 31 and then separatedinto alternate sets as described hereinbefore. One of these sets is ledaround the driving roll 22 of the lower winding device, whereas theother is let upwardly around the driving roll 22 of the upper windingdevice, after which both sets are wound in the same manner.

The tapes 3t) are led into the nip between the driving roll 22 and theirrespective cores 33 on the mandrel 21 with the adhesive side of the tapein contact with the peripheries of the cores 33 and then wound aroundthe cores to form the tape rolls 32. Since the cores 33 are free torotate on the mandrel, their rotation is controlled directly by therotation of the driving roll 22 in contact therewith through the tapesbeing wound on the cores as best shown in FIGS. 1-4. The cores 33 andthen the tape rolls 32 are urged into compressive contact with theresilient surface portion 38 of the driving roll 22 by the downwardpressure exerted upon the cores from the weighted roll 23. This pressureis applied by the weighted roll to the tape rolls 32, themselves, andthrough the tape rolls to the mandrel 21. Thus, if any of the tape rolls32 are not contacted directly by the weighted roll 23, due to the factthat they have become smaller in diameter during winding, theynevertheless are urged downwardly by the weighted roll through themandrel. As explained hereinbefore, the resilient surface portion 38 ofthe driving roll is sutficiently thick and compressible that it absorbsany variations which may occur in the diameter of the tape rolls 32being wound on the mandrel 21 due to variations in the thickness of thetape backing or the tape itself or any other cause. This is illustratedin FIGS. 3 and 4 where a roll of larger diameter is shown in FIG. 4 thanFIG. 3, with the roll of FIG. 4 consequently sinking further into theresilient portion 38 of the driving roll. However, in both casesintimate driving contact is maintained between the driving roll 22 andthe tape roll 32.

It also should be noted that the tapes 30 are wrapped around asubstantial portion of the periphery of the driving roll 22 and the taperolls 32, and prior to any contact between the adhesive side of thetapes and the tape rolls. This amount of contact area between thenon-adhesive surfaces of the wrapped tapes 3t) and the periphery of theresilient portion 38 of the driving roll is sufiicient to assure thatthere normally is no slippage between the tapes 30 and the driving roll22, in view of the relative coefficients of friction of the materials incontact with one another. Thus, each of the tapes moves into the nipbetween the driving roll 22 and its respective tape roll 32 at thelinear speed of the periphery of the driving roll 22 and is wound uponthe tape roll substantially at this linear speed. This assures that thetape rolls 32 are wound at relatively constant tension well within theacceptable range of roll tightness as measured by the normal hardnessstandards established for this purpose and explained hereinbefore.

When the tape rolls 32 are wound in this manner with the resilientperipheral surface portion 38 of the driving roll 22 contacting all ofthe tape rolls through the tapes being wound thereon at the points wherethese tapes first contact their respective rolls in such a way that thetape rolls 32 sink into the resilient portion 38 of the driving roll atleast to the extent illustrated schematically in FIGS. 3 and 4; air isexpressed Sllfl'lCiEIltlY from between the tape convolutions being woundon the roll to produce a brilliantly clear roll of tape when all of thetape components are normally transparent. While the exact mecha nism bywhich this is accomplished is not known, it is believed that it isattributable to the relative forces created by the distortion of theresilient portion 38 of the driving roll as the tape is being wound onthe freely rotating tape cores. It also is important that the amount ofpressure exerted between the driving roll 22 and the tape rolls 32 iscontrolled relatively evenly along the mandrel 21, with only slightvariations occurring between tape rolls of somewhat different size.Thus, with the close control obtainable in winding tape rolls inaccordance with this invention, whole sets of transparent tape rolls maybe wound on the same mandrel with virtually the same hardness andclarity.

Referring to FIGS. 19-26, a preferred embodiment of apparatus accordingto this invention is shown, wherein the tape rolls 32 are rotatablymounted on an improved expandable mandrel 101, and the tape rolls andthe mandrel are pressed into contact with the resilient peripheralportion of the driving roll 22 by a set of resilient pressure wheels 102rotatably mounted on a control shaft 103, laterally on the opposite sideof the mandrel from the driving roll 22. Each end of the control shaft103 is journaled in a ball bearing 104 fitted in opposed end bloc ks 105each of which is fixed to a nonrotatable support shaft 106. As is thecase for FIG. 2, only one end of the unit of FIGS. 19-26 is shown inFIG. 19 for the sake of simplicity since the other end is identical. Theends of the support shaft are connected to a pair of square end slides107 which are guided for vertical movement towards and away from thedriving roll 22 by corresponding vertical tracks 108 shown on theoutside of the end frame 36 which rotatably supports the drive shaft forthe driving roll 22. The control shaft 103, the pressure wheels 102rotatably mounted thereon, the support shaft 106 and the end blocks 105,together provide a pressure applying unit which presses the tape rolls32 and the mandrel 101 into intimate contact with the resilient portionof the driving roll 22 through direct contact between the pressurewheels 102 and the tape rolls 32. As explained in connection with theembodiment of FIGS. 1-14, each of the slides 107 is pulled downwardly bya chain 109 attached to the arm of an eddy current clutch, not shown,which is adjustable to deliver a balanced pulling force on each end ofthe unit and to control the amount of pressure which the pressure wheels102 exert upon the tape rolls 32 in urging them into contact with thedriving roll 22. The control shaft 103 is guided for this purpose by apair of cam follower rolls 110 which ride in vertical guide tracks 110asecured to the end frame 36. The follower rolls 110 are threaded intothe ends of the shaft 103.

The pressure wheels 102, themselves, each comprise an annular mountingrim 111 having a flat peripheral mounting portion 112 and opposedprojecting flanges 113, and a compressible and resilient annular ring114 which fits between the flanges 113 of the rim 111 and grips the fiatmounting portion 112 thereof so that the ring 114 rotates as a unit withthe rim 111. The rims 111 and, correspondingly, the pressure wheels 102are mounted to rotate freely on the control shaft 103 independently ofone another, but are positioned axially on the shaft as a set by collars115 secured to the shaft 103 with a set screw 116. The outside annularsurfaces of the rims 111 and the flanges 113 are curved convexly so thatonly a very limited circular portion of one rim contacts a correspondingportion of the next adjacent rim on each side of each pressure wheel102, thereby minimizing frictional drag between adjacent wheels.

It will be seen most clearly from FIGS. 21 and 22 that the tape rolls 32are positioned axially on the mandrel 101 by circumferentially extendingannular spacing recesses 117 which the tape cores 3 3 fit into when themandrel is expanded. The axial spacing between the recesses 117 andtherefore the cores 33 and the tape rolls 32, is greater than the axialwidth of the resilient rings 114 at their periphery, thereby assuringthat a given pressure wheel 102 can not contact more than one tape roll32 simultaneously. Thus, with the dimensional relationships shown inFIG. 21, each tape roll. 32 normally is being pressed towards thedriving roll 22 by two of the resilient pressure wheels 102 but under nocircumstances can a single pressure wheel 102 bridge the gap between twotape rolls 32. This assures that the pressure wheels 102 will not exertany appreciable drag on the tape rolls 32 and that the tape rolls willremain capable of turning at different angular speeds with respect toone another even though their surface linear speeds are constant acrossthe driving roll 22. This relationship is very important since, in thisembodiment of the invention, the peripheries of the tape rolls 32 enterinto strong frictional engagement with the resilient and compressiblerings 114 of the pressure wheels 102 and would not be able to turnindependently of one another if the rings bridged the distance betweentape rolls.

The rings 114 preferably are quite resilient and may be molded from puregum rubber whereas the rims 111 preferably are formed of brass oranother material possessing good bearing characteristics. Thus, thepressure wheels 102 are capable of exerting continuing downward pressureon each of the tape rolls 32 directly through the rings 114 to pressthem into the resilient surface portion of the driving roll 22 andthereby establish the desired surface winding relationship describedhereinbefore. In fact, the very resilient nature of the individual rings114 allows this relationship to be established even though there isconsiderable clearance between the inner diameters of the tape cores 33and the outer diameters of the circumferential recesses 117 in themandrel 101.

FIGS. 21-25 show the expandable mandrel 101 of this invention in moredetail. Again only one end of the mandrel is shown for simplicity sinceboth of its ends are identical. This mandrel is particularly suited forhandling tape rolls wound on relatively large diameter cores. Themandrel 101 comprises a pair of semi-cylindrical halves, i.e., a topshell 121 and a bottom shell 122 normally urged into contact with oneanother to form a full cylinder by a pair of girth springs 123, locatedone at each end beyond the tape rolls 32. This position of the shells121 and 123 is shown in FIG. 25 and is the one wherein the mandrel isradially retracted to allow the tape cores 33 to be slid axially intoposition aligned with their respective annular spacing recesses 117.

A semi-cylindrical top end cap 124 is fitted into and over each end ofthe top shell 121, and a corresponding bottom end cap 125 is fitted intoand over each end of the bottom shell 122, with the two end caps fittingtogether at each end to close the cylinder. Each end ca 124 and 125 issecured to the end of its respective: cylinder by bolts 126 and presentsa semi-cylindrical inwardly extending shelf, 128 on the top caps 124,and 129 on the bottom caps 1 1 125, which fit into the shells andstructurally supports them. The bottom end caps 125 includes an integraloutwardly extending cylindrical boss 131 and the top end caps 124 arerelieved to receive the bosses 131 when the two end caps are broughttogether at each end of the mandrel.

A knurled cam control wheel 132 is rotatably fitted over the boss 131 ateach end of the mandrel where it is held in position axially by aC-spring 133 which snaps into an annular groove 134 in the boss. Acamming rod 135 extends inwardly from each of the control wheels 132through a curved arcuate slot 136 in its respective bottom end cap 125.The rod 135 is moved from the top of the slot 136, where it is shown inFIG. 25, towards the bottom of the slot, where it is shown in FIGS. 23and 24, simply by rotating the control wheel 132 clockwise, referring toFIGS. 23-25. Movement of the rod 135 in this direction brings it intocontact with the inclined camming surface 137 of a cam follower plate138 secured to the top end plate 124 by bolts 139. The cam plate 138rests in a vertical slot 141 in the shelf 129 of the bottom end plate125 for vertical movement therein. Thus, the cam follower 138 is drivenupwardly as the camming rod 135 is turned beyond point 142 in FIG. 25and thence moved towards the bottom of the slot 136. When the rod 135reaches the bottom of the slot, it assumes a position under the camfollower 138, as shown in FIG. 24, and holds the mandrel in its expandedposition shown in FIGS. 22-24. A spring loaded ball detent 143 isprovided in the control wheel 132 to fit into a recess 144 in the boss131 to prevent the rod 135 from being accidentally misplaced from theposi tion shown in FIG. 24 during operation of the unit. Of course, assoon as the detent 143 is displaced from the recess 144 and the cammingrod 135 is moved to the right in FIG. 24 (out from under the camfollower 138) the springs 123 will pull the two halves of the mandreltogether to return all parts to the position shown in FIG. 25.

In the retracted position of the mandrel 101, shown in FIG. 25, the tapecores 33 will be slightly larger in inner diameter than the maximumouter diameter of the man drel 101 taken between the annular recesses117, thereby assuring that the cores 33 can be properly positionedaxially on the mandrel as explained hereinbefore. The recesses 117preferably are cut to a depth which will result in the expanded mandrelouter diameter across the bottoms of the recesses approximately beingequal to the maximum retracted outer diameter of the mandrel. Thus therecesses 117 may vary from a negligible depth at the side edges of theshells to their full depth at the top of the shell 121 and the bottom ofthe bottom shell 122 in the positions shown in the drawings.

The mandrel 101 is mounted for rotation on cylindrical cam followers 146threaded into the bosses 131 and the followers 146 ride in the guidetracks 110a for guiding the mandrel as it is urged toward and away fromthe driving roll 22.

Having now described the invention in specific detail and exemplifiedthe manner in which it may be carried into practice, it will be readilyapparent to those skilled in the art that innumerable variations,modifications, aplications and extension of the basic principlesinvolved may be made without departing from its spirit or scope.

What is claimed is:

1. A differential surface winder for simultaneously winding a pluralityof pressure-sensitive adhesive tapes slit from the same sheet into acorresponding number of tape rolls wherein the tapes are wound uponthemselves on cylindrical cores with the adhesive side of the tapesfacing inwardly, which comprises a mandrel having circumferentialportions adapted to receive said cores and mount them rotatably withrespect to said mandrel, spacing means associated with said mandrel formaintaining said rolls in definite positions axially spaced from oneanother on said mandrel but Without interfering with their rotation withrespect thereto, said spacing means being movable laterally with respectto the axis of the mandrel in a direction perpendicular to said axisfrom a first position wherein the spacing means does not interfere withthe axial sliding movement of the tape cores on or off the mandrel to awinding position wherein the tape cores are retained in position axiallyon the mandrel by the spacing means while being allowed to rotate freelythereon during winding, means for retaining said spacing means in theaforesaid operating relation with respect to the axis of the mandrelduring winding, a driving ro'll disposed in axial parallelism withrespect to said mandrel and presenting a relatively compressible andresilient peripheral surface portion adapted to contact all of the taperolls on said mandrel, and means for urging said mandrel and saiddriving roll towards one another with sufficient force that theperipheries of said tape rolls sink at least slightly into theperipheral surface portion of said driving roll to provide intimatedriving contact between the driving roll and the tape rolls, saidperipheral surface portion being sufficiently compressible to allow atape roll which acquires a somewhat larger diameter to sink further intosaid driving roll than tape rolls of smaller diameter while maintainingdriving contact with each of the tape rolls on said mandrel.

2. A differential surface winder according to claim 1, wherein theresilient peripheral surface portion of said driving roll is adapted tocontact all of said tape rolls through said tapes at the points wheresaid tapes first contact their respective tape rolls.

3. A differential surface winder according to claim 2, which furthercomprises means for wrapping the tapes around a substantial portion ofthe periphery of the driving roll with the non-adhesive side of the tapein contact with the surface of the driving roll prior to any contactbetween the adhesive side of the tape and the tape rolls.

4. A differential surface winder according to claim 3, wherein the areaof contact between the wrapped tapes and the periphery of the drivingroll and the coefficient of friction between the non-adhesive surfacesof the tapes and the resilient outer surface of the driving roll aresuch as to normally prevent slippage between the tapes and the drivingroll during winding of the tape.

5. A differential surface winder according to claim 1, wherein themandrel is mounted in such a way as to be freely rotatable.

*6. A differential surface winder according to claim 2, wherein themeans for urging said mandrel towards the driving roll is a pressureroll disposed on the opposite side of said mandrel from said drivingroll and in axial parallelism therewith in such a way that said pressureroll normally rests on the tape rolls themselves and through the taperolls urges the mandrel towards the driving roll.

7. A differential surface winder according to claim 6', wherein saidpressure roll is urged towards said mandrel by control means at each endof said pressure roll.

8. A differential surface winder according to claim 6, wherein saidpressure roll is a weighted roll.

9. A differential surface winder according to claim 1, wherein theresilient peripheral surface portion of said driving roll possesses aShore-A durometer hardness of about 25-35.

10. A differential surface winder according to claim 9, wherein saidresilient peripheral surface portion is in the form of a hollow cylindersurrounding a central cylindrical portion of said driving roll and saidhollow cylinder is at least about one quarter inch thick.

11. A differential surface winder according to claim 1, wherein saidmandrel includes a series of spacing members which are adapted to beretracted radially with respect to the axis of the mandrel to allow freemovement of the tape cores axially on the mandrel, and ex- 13 tendedradially with respect to the axis of the mandrel to position the taperolls axially of the mandrel and prevent their further movement in thisdirection while allowing free rotation of the cores on the mandrel.

12. A differential surface winder according to claim 11, wherein saidspacing members are completely retractable into said mandrel to allowaxial movement of the tape cores on the mandrel.

13. A differential surface winder according to claim 12, wherein saidspacing members are adapted to be moved inwardly and outwardly of themandrel as a set and are spring loaded in one direction and camcontrolled in the other direction.

14. A differential surface winder for simultaneously winding a pluralityof pressure-sensitive adhesive tapes slit from the same sheet into acorresponding number of tape rolls wherein the tapes are wound uponthemselves on cylindrical cores with the adhesive side of the tapesfacing inwardly, which comprises a mandrel having circumferentialportions adapted to receive said cores and mount them rotatably withrespect to said mandrel, spacing means associated with said mandrel formaintaining said rolls in definite positions axially spaced from oneanother on said mandrel but without interfering with their rotation withrespect thereto, means for retracting said spacing means transverselywith respect to the axis of the mandrel to allow free movement of thetape cores axially on the mandrel and for extending said spacing meanstransversely with respect to the axis of the mandrel to position thetape rolls axially on the mandrel while allowing them to rotate freelythereon as aforesaid, a driving roll disposed in axial parallelism withrespect to said mandrel and presenting a relatively compressible andresilient peripheral surface portion adapted to contact all of the taperolls on said mandrel and means for urging said mandrel and said drivingroll towards one another with suflicient force that the peripheries ofsaid tape rolls sink at least slightly into the peripheral surfaceportion of said driving roll to provide intimate driving contact betweenthe driving roll and the tape rolls, said peripheral surface portionbeing sufficiently compressible to allow a tape roll which acquires asomewhat larger diameter to sink further into said driving roll thantape rolls of smaller diameter while maintaining driving contact witheach of the tape rolls on said mandrel, and said tape rolls beingrotatably driven only through the aforesaid contact with said drivingroll.

15. A differential surface winder for simultaneously winding a pluralityof pressure-sensitive adhesive tapes slit from the same sheet into acorresponding number of tape rolls wherein the tapes are wound uponthemselves on cylindrical cores with adhesive side of the tapes facinginwardly, which comprises a mandrel adapted to receive said cores andmount them rotatably with respect to said mandrel, spacing meansassociated with said mandrel for maintaining said rolls in definitepositions axially spaced from one another on said mandrel but withoutinterfering with their rotation with respect thereto, a driving rolldisposed in axial parallelism with respect to said mandrel andpresenting a relatively compressible and resilient peripheral surfaceportion adapted to contact all of the tape rolls on said mandrel, aplurality of pressure wheels mounted for rotation independently of oneanother in a set disposed in axial parallelism with respect to saidmandrel and laterally on the opposite side of said mandrel from saiddriving roll, said pressure wheels being adapted to contact radiallyopposite portions of said tape rolls from those portions contacted bysaid driving roll and being arranged axially with respect to the taperolls on said mandrel so that no one of said wheels will contact morethan one of said tape rolls, and means for urging said pressure wheelsand said driving roll towards one another with sufliicent force that thepressure wheels press said tape rolls against said driving roll and theperipheries of said tape rolls sink at least slightly into the 14peripheral surface portion of said driving roll to provide intimatedriving contact between the driving roll and the tape rolls, saidperipheral surface portion being suflicient- 1y compressible to allow atape roll which acquires a somewhat larger diameter to sink further intosaid driving roll than tape rolls of smaller diameter while maintainingdriving contact with each of the tape rolls on said mandrel.

16. A differential surface winder according to claim 15, wherein theaxial width of the individual pressure wheels at their periphery is lessthan the axial distance between adjacent tape rolls on said mandrel.

17. A differential surface winder according to claim 15, wherein saidpressure wheels are compressible and resilient and thereby adapted toaccommodate tape rolls of slightly different diameters.

18. A differential surface winder according to claim 15, which comprisesa control shaft on which said pressure wheels are rotatably mounted.

19. A differential surface winder according to claim 18, wherein saidcontrol shaft is urged towards said mandrel by control means at each ofits ends and said control means is adjustable to regulate the force bywhich said pressure wheels press the tape rolls against said drivingroll.

20. A differential surface winder according to claim 19, wherein saidpressure wheels comprise compressible and resilient peripheral portionsfor contacting said tape rolls.

21. The method of manufacturing a roll of clear-tothe-corepressure-sensitive adhesive tape from a length of normally clear andtransparent tape comprising a transparent film backing and a layer of atransparent pressure-sensitive adhesive on one side of said backingwhereby the tape has an adhesive side and a non-adhesive side, whereinthe tape length is wound upon itself about a core with the adhesive sideof the tape facing inwardly toward the axis of the roll and thenon-adhesive side of the tape facing outwardly away from the axis of theroll; which comprises mounting said core on a winding mandrel, freelyrotating said core (with respect to) on said mandrel and winding thetape by rotating the tape roll only by contact between the outernon-adhesive surface of the tape roll and the surface of a compressibleand resilient peripheral portion of a driving roll, and urging the taperoll and the driving roll against one another with sufficient force tocause a circumferential portion of the tape roll to sink into theresilient portion of the driving roll during said winding and press theadhesive layer in the newly formed outermost convolution of the taperoll smooth and into intimate contact with the outer non-adhesivesurface of the adjacent inner convolution of said tape roll and therebyexpress the air from between said convolutions as the adhesive layer ofthe newly formed outermost convolution of said tape becomes adhered tothe non-adhesive outer surface of the said adjacent inner convolution,the tape first contacting said tape roll at one edge of thesunk-in-circumferential portion of the tape roll.

22. The method of manufacturing a roll of tape according to claim 21,wherein the tape is wrapped around a substantial portion of the drivingroll in contact with the surface of the compressible and resilientportion of said driving roll prior to any contact between the adhesivelayer of the tape and the tape roll, the said contact between the tapeand the driving roll being such as to normally prevent slippage betweenthe tape and the driving roll.

23. The method of manufacturing a roll of tape according to claim 21,wherein a plurality of cores are mounted on said mandrel in such a wayas to remain freely rotatable while being retained in axially spacedrelation from one another and a corresponding plurality of tape rollsare wound thereon, said tape rolls being urged as a set against saiddriving roll and the peripheral portion of the driving roll issufficiently resilient to maintain driving contact with each of the taperolls on said mandrel despite slight differences in the outer diametersof said tape rolls.

24. The method of manufacturing a roll of tape according to claim 23,wherein said tape rolls are urged against said driving roll by applyingpressure to the peripheral surface of each tape roll on the side of thetape rolls radially opposite to that contacting said driving roll.

25. A dimensionally stable and clear-to-the-core roll ofpressure-sensitive adhesive tape made in accordance with the method ofclaim 21.

References Cited UNITED STATES PATENTS Rockstrom et al. 242-65 Larsen eta1 242-569 Luchansky 242-569 -Deichert 242-569 X Brown 242-569 Crowe242-569 Amos 242-569 Schmidt et a1. 242-569 X Bretson .et a1. 242-685US. Cl. X.-R.

